Exposure to Lead Appears to Selectively Alter Metabolism of Cortical Gray Matter

Abstract

Objective. The effects of lead poisoning on the development of children have been examined primarily in the context of behavioral and neuropsychological studies. The purpose of this study was to examine the in vivo use of magnetic resonance spectroscopy (MRS) for the evaluation of the neurotoxic effects of lead on the nervous system. MRS has the ability to monitor brain metabolism by detecting a number of neurochemicals among which is N-acetylaspartate, a metabolite shown to decrease in processes that involve neuronal loss. Methods. In the present study we evaluated the metabolism of gray and white matter of frontal cortex using MRS in individuals with elevated blood lead levels and compared the results with those obtained on nonlead-exposed controls. Results. Although all of the participants had normal MRI examinations of the brain, the lead-exposed individuals exhibited a significant reduction in the N-acetylaspartate/creatine and phosphocreatine ratios in frontal gray matter compared with the nonlead-exposed controls. Conclusions. The findings of this study suggest that lead has an effect on brain metabolites as detected by MRS in vivo. More specifically, we have found statistically significant reduced levels of brain metabolites in gray but not white matter in lead-exposed individuals. These results imply that MRS is able to detect metabolic abnormalities in individuals with lead poisoning.